2022 Technical Division Student Poster Contest: LMD 2022 Technical Division Graduate Student Poster Contest
Program Organizers: TMS Administration

Monday 5:30 PM
February 28, 2022
Room: Exhibit Hall C
Location: Anaheim Convention Center

SPG-18: A Promising Orthopedic Implant Material with Enhanced Corrosion Resistance, Mechanical Properties, Osteogenic and Antibacterial Activity: Mg-Sc-Sr Alloy: Nadia Aboutalebianaraki1; Sudipta Seal1; Mehdi Razavi1; 1University of Central Florida
    Magnesium (Mg) alloys have gained interest in orthopedic applications due to their low density, biodegradability, and close mechanical properties to cortical bone. However, the rapid corrosion of Mg leads to high hydrogen gas evolution. We used scandium (Sc) and strontium (Sr) as alloying elements to construct an Mg-Sc-Sr ternary alloy to address this shortcoming. The effects of alloying elements and heat treatment on the microstructure, corrosion, mechanical properties, antimicrobial activity, and osteoconductivity of the Mg alloy were evaluated. The Mg-Sc-Sr showed a reduction in the corrosion rate, hydrogen evolution, and enhancement in the yield strength compared to Mg and also induced osteoblastic differentiation in vitro without showing toxicity. Additionally, microbiological counting, confocal microscopy, and scanning electron microscope (SEM) in vitro consistently demonstrated that Mg-Sc-Sr enhanced antibacterial activity compared to Mg. Based on our results, the Mg-Sc-Sr alloy is a promising candidate as a bone implant.

SPG-19: Development of Equiaxed Titanium Alloys in Additive Manufacturing: Nevin Taylor1; 1Ohio State University
    Commercial titanium alloys such as Ti-64, which are widely used in additive manufacturing today, have anisotropic properties due to large prior beta grains that develop during additive manufacturing. This research investigates alloying elements that expand the freezing range and induce a columnar to equiaxed transition at rather low alloying content. It has been shown that beta-eutectoid elements including Iron, Nickel and Cobalt at ~3wt% will induce a fully equiaxed microstructure with grains an order of magnitude smaller than in their counterpart alloys. The mechanical properties or these newly developed alloys also shows significant promise, as they have increased strength, as well as similar ductility. Post-build heat treatments also introduce possibilities for different properties and microstructures depending on the desired application.

SPG-20: Effects of Cu on the Interfacial Stability of Nanoprecipitates in Al-Zn-Mg-Cu Alloys from First-principles Investigations: Yu-ning Chiu1; Chung-yi Yu2; Shih-kang Lin1; 1National Cheng Kung University; 2China Steel Corp, Aluminum Prod R&D Sect
    The benefit of Cu on preventing thermally induced precipitate transitions and resultant softening in 7000 series aluminium alloys (Al-Zn-Mg-Cu alloys) has been well studied over the past decades. However, the stabilization mechanism of Cu has yet been understood clearly. As a result, the interfacial structures and energetics of nanoprecipitates η’ and η2 in Al-Zn-Mg-Cu alloys were thoroughly investigated through first-principles calculations. The most feasible interfacial structures for η’ and η2 with Cu segregated in were constructed, and with which, a comprehensive discussion on interfacial energy and strain energy as well as atomic local strain hydrostatic invariant (ALSHI) were provided to study the effect of Cu. In this study, we concluded that the main driving force for induced interfacial segregation and resultant stabilization were mostly contributed from the relieved strain energy. Thus, ALSHI can serve as a considerably useful guideline for optimal interfacial segregation and future alloy design of Al-Zn-Mg-Cu alloys.

SPG-21: Fatigue Behavior of Fastener Holes in High-strength Aluminum Plates Repaired by Additive Friction Stir Deposition: Ismael Hidalgo1; Paul Allison1; Brian Jordon1; Malcolm Williams1; Jacob Strain1; Bret Cordle1; Troy Pierson1; Jacob Williamson1; James Tew1; 1The University of Alabama
    Fastener holes often serve as damage initiation sites in aluminum aircraft structures. This present study will characterize the potential for solid-state additive manufacturing techniques, namely additive friction stir deposition (AFSD), in repairing high-strength aluminum alloy 7050. This study uses a blended-out center hole geometry to simulate mechanically or corrosively damaged material that commonly occurs around fastener's holes. The microstructure of the repaired specimen will be characterized to evaluate the repair interface and the effect of heat input during processing on the substrate material. Monotonic and fatigue properties will be assessed for a repaired and unrepaired specimen to quantify the structural performance of the repairs. Post-testing fractography will elucidate the failure mechanisms from both cyclic and overload testing to understand the weaknesses and strengths of the process in repairing AA7050. As such, this study will demonstrate the potential for solid-state manufacturing to return damaged components to service.

SPG-22: Microstructural Evolution during Post Processing of Additively Manufactured 7050 Aluminum Alloy and Its Effect on Corrosion Behavior: Rupesh Rajendran1; Crosby Owens2; David Spain2; Preet Singh1; 1Georgia Institute of Technology; 2Northrop Grumman Aeronautics Systems
    High strength 7xxx aluminum alloys fabricated via additive manufacturing process are promising candidates for aerospace applications but there has been limited adoption of these alloys due to defects such as hot tearing and solidification cracking. Addition of nanoparticles or inoculants has been reported to promote equiaxed grain growth, mitigating such defects. This work aims to explore the microstructural evolution of additively manufactured (AM) 7050 aluminum alloy with equiaxed grains, during different stages of post-processing treatments – as built condition, partial annealing, hot isostatic pressing and solutionizing and ageing. Localized corrosion behavior of AM 7050 alloys is studied using immersion and scanning vibration electrode technique, giving insights on how different microstructural features lead to differences in local corrosion behavior. The results are compared with an equivalent wrought 7050 alloy for consideration of AM 7050 alloys as potential candidates for aerospace applications.

SPG-23: Prior Grain Boundary Alpha in BASCA Ti-17: Mathew Cohen1; 1The Ohio State University
    Metastable beta titanium alloys offer attractive properties given their ability to form refined microstructures. However, allotriomorphic alpha at the grain boundaries often limits the ductility in these alloys. A beta anneal slow cool age (BASCA) heat treatment is often used with Ti-5553. Ti-5Al-2Sn-2Zr-4Cr-4Mo (Ti-17) is also an excellent material to undergo a BASCA heat treatment as it is beta rich and has a relatively low beta transus. In this study, Ti-17 underwent a variety of different whole and partial BASCA heat treatments, mainly resulting in basketweave microstructures. The grain size, as well as the ratio of grain boundaries with and without allotriomorphic alpha, were evaluated with different heat treatment parameters, and it was found that higher cooling rates resulted in less alpha lathes on the grain boundaries. Scanning electron microscopy (SEM) in conjunction with back scattered electron (BSE) imaging was used to study the material after heat treatment.

SPG-24: Thermomechanical Processing of Aluminum-Cerium Alloys: Elizabeth Heon1; Eric Lass1; 1University of Tennessee Knoxville
    Aluminum-cerium (Al-Ce) alloys are a promising alternative to conventional aluminum alloys for medium temperature (approximately 250-400C) applications, as they demonstrate superior elevated temperature strength retention. The development of Al-Ce alloys has primarily focused on cast products, as the Al-Ce eutectic system demonstrates excellent castability. The elevated temperature mechanical properties of these alloys also make them attractive for wrought applications; however, a significant research gap exists in this area, as only a handful of studies have examined the thermomechanical processing of Al-Ce alloys. Al-Ce alloys are reinforced by a eutectic phase which fractures upon deformation; key to the development of these alloys for wrought product will be preventing cavitation at the particle/matrix interface. This work aims to understand the response of binary and multi-component Al-Ce alloys to thermomechanical processing. The effect of degree of deformation and annealing on the microstructure and mechanical properties is explored.